William Baird may refer to:
- William Baird (MP) (1796–1864), Conservative MP for Falkirk Burghs
- William Baird (physician) (1803–1872), Scottish physician and zoologist
- William Baird (footballer) (1874–1943), Scottish footballer
- William Alexander Baird (1867–1940), Ontario lawyer and politician
- William L. Baird (1843–1916), Massachusetts politician
- William M. Baird (1862–1931), American Presbyterian missionary
- William Raimond Baird (1848–1917), publisher of Baird's Manual of American College Fraternities
- William Teel Baird (1819–1897), New Brunswick historian